Conventionally, observation apparatuses having a phase-modulating spatial light modulator (liquid-crystal-on-silicon spatial light modulator: LCOS-SLM) are known (for example, see PTLs 1 and 2 below).
The observation apparatus disclosed in PTL 1 includes an LCOS, two galvanometer mirrors, and a relay optical system that relays the pupils of the two galvanometer mirrors. The wavefront of the laser light modulated by the LCOS is accurately relayed, via the two galvanometer mirrors, to an entrance pupil position of an objective optical system by the relay optical system. Thus, a laser scanning microscope (LSM) observation can be performed without deteriorating the light collecting ability.
The observation apparatus disclosed in PTL 2 includes an illumination light path in which the wavefront of the laser light is modulated by an LCOS and an illumination light path in which the laser light is scanned by a two-dimensional scanner. By simultaneously radiating the laser light in these illumination light paths onto a specimen, pattern illumination with the LCOS and LSM observation using the two-dimensional scanner can be simultaneously performed.